DESCRIPTION Much research has identified the amygdala as a critical brain region for emotions, in particular fear. Disorders of fear processing result in debilitating psychopathologic conditions in humans, such as anxiety, phobias and post-traumatic stress disorders, and its is widely believed that these disorders involve learning processes. The ultimate goal of this proposal is to investigate the way in which this experience dependent learning is encoded in the brain. The fear system is an ideal one in which to study the neuronal bases of such learning because, unlike many other systems, the learning occurs rapidly, at a defined point in time, and the relation between specific synaptic circuits and the behavior is better defined than in many other paradigms used. Thus, this research plan will use the in vitro brain slice preparation of the amygdala, and in vivo intracellular recording techniques to directly examine the role of plasticity at input synapses to the amygdala in conditioning. A better understanding of the neural mechanisms underlying emotional behaviors may facilitate the development of therapeutic strategies for aiding people who suffer from psychological disorders.